nir: Print divergence status of SSA values if analysis was ever run.

After running divergence analysis, we include "div" or "con" for each
SSA def's divergence/convergence status:

	vec1 32 div ssa_35 = fddy ssa_34
	vec1 32 con ssa_36 = fddy ssa_6.x

We omit this before the first time divergence analysis has been run.

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15445>

src/compiler/nir/nir_divergence_analysis.c

@@ -993,6 +993,8 @@ visit_cf_list(struct exec_list *list, struct divergence_state *state)
 void
 nir_divergence_analysis(nir_shader *shader)
 {
+   shader->info.divergence_analysis_run = true;
+
    struct divergence_state state = {
       .stage = shader->info.stage,
       .shader = shader,

src/compiler/nir/nir_print.c

@@ -106,8 +106,13 @@ static void
 print_ssa_def(nir_ssa_def *def, print_state *state)
 {
    FILE *fp = state->fp;
-   fprintf(fp, "%s %u ssa_%u", sizes[def->num_components], def->bit_size,
-           def->index);
+
+   const char *divergence = "";
+   if (state->shader->info.divergence_analysis_run)
+      divergence = def->divergent ? "div " : "con ";
+
+   fprintf(fp, "%s %2u %sssa_%u", sizes[def->num_components], def->bit_size,
+           divergence, def->index);
 }
 
 static void

src/compiler/shader_info.h

@@ -254,6 +254,9 @@ typedef struct shader_info {
     */
    bool uses_fddx_fddy:1;
 
+   /** Has divergence analysis ever been run? */
+   bool divergence_analysis_run:1;
+
    /* Bitmask of bit-sizes used with ALU instructions. */
    uint8_t bit_sizes_float;
    uint8_t bit_sizes_int;